Subintimal Reentry Catheter Balloon Deflection Mechanism

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Solution Overview

Problem

Current methods for recanalizing occluded blood vessels, particularly those with chronic total occlusions, face challenges in reentering the true lumen from the subintimal space due to increased stiffness of the intimal layer caused by calcification, leading to risks of vessel perforation or dissection.

Innovation Solution

A subintimal recanalization catheter system is developed, featuring an elongate shaft with an extension segment and a balloon catheter that inflates against the extension segment to deflect the catheter shaft toward the lumen, facilitating reentry into the true lumen of the blood vessel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional subintimal reentry methods are used, then recanalization can be attempted, but the risk of vessel perforation or dissection increases due to calcification-induced stiffness

Engineering Contradiction:

Improverecanalization successVSAvoidvessel perforation risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical parameters of the reentry system by incorporating an extension segment with different stiffness characteristics than the main catheter shaft. This allows the system to adapt to the increased stiffness caused by calcification while maintaining control and reducing perforation risk through optimized mechanical properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The catheter system uses composite construction with an extension segment that has distinct material properties from the main shaft. This composite structure enables the device to navigate calcified vessels safely while maintaining the ability to reenter the true lumen, addressing both reliability and safety concerns

Inventive Principle:

Principle #40Composite materials

2Strength

If calcified intimal layer stiffness increases, then vessel wall strength improves, but the difference in stiffness between tissue layers decreases making reentry difficult

Engineering Contradiction:

Improvevessel wall strengthVSAvoidreentry difficulty

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The extension segment is designed with specific stiffness parameters that differ from both the main catheter shaft and the calcified intimal layer. This parameter optimization allows the device to penetrate through calcified tissue when needed while maintaining overall vessel wall strength and preventing damage

Inventive Principle:

Principle #35Parameter changes

3Force

If a stiffer catheter is used to penetrate calcified occlusion, then penetration ability improves, but the risk of inadvertent perforation or dissection increases

Engineering Contradiction:

Improvepenetration forceVSAvoidperforation or dissection risk

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The catheter system applies local quality by providing different stiffness characteristics at different segments - the extension segment has higher local stiffness for penetrating calcified tissue, while the main shaft maintains lower stiffness for safe navigation and control, thereby achieving penetration force without proportional increase in perforation risk

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The catheter is divided into functional segments with different mechanical properties. The extension segment specifically addresses penetration needs through calcification, while the separate main shaft maintains overall system safety and controllability, allowing force application without proportional increase in harmful effects

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the ability to safely and effectively reenter the true lumen, reducing the risk of vessel damage and improving recanalization success rates in vessels with occlusions.

Implementation Method 1

The balloon may be configured to be inflated against the extension segment to cause a distal portion of the catheter shaft to deflect toward the lumen of the blood vessel within the subintimal space

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

cause a distal portion of the catheter shaft to deflect toward the lumen

Methodology Applied

Scientific EffectElastic deformation: Deformation

Data Source

PatentEP2872209B1Subintimal reentry system

Publication Date: 2018.06.20 BOSTON SCIENTIFIC SCIMED INC

Figure 1A~1B
Figure 1C~2
Figure 3A~3B

AI summary

A subintimal recanalization catheter system for recanalizing a blood vessel. The system includes a support catheter and a balloon catheter configured to extend through the support catheter. The support catheter includes a tubular portion and an extension segment extending distal of the distal opening of the tubular portion. The balloon catheter, having a balloon secured to a distal portion thereof, is positionable through the tubular portion of the support catheter to position the balloon alongside the extension segment. The system is configured to be advanced into a subintimal space between a first tissue layer and a second tissue layer of a blood vessel wall where the balloon may be inflated against the extension segment to cause a distal portion of the catheter shaft of the balloon catheter to deflect toward the vessel lumen within the subintimal space to facilitate reentry into the vessel lumen.